Exercise increases heart rate and cardiac output and is helpful in the determination of dynamic mitral gradient in patients with mitral stenosis. However exercise is difficult to perform during cardiac catheterization in a premedicated recumbent patient and is only feasible when the brachial approach is used. Therefore, in the haemodynamic laboratory, exercise has important practical limitations. In order to obtain similar information using a reproducible and non-invasive technique, we tested the feasibility of combined two-dimensional and continuous wave Doppler echocardiography during exercise in a selected number of patients with pure mitral stenosis and in sinus rhythm. Seven patients, ranging from 14 to 48 years (average: 35 +/- 13), underwent baseline two-dimensional and continuous wave Doppler examinations, repeated after 2 minutes of supine bicycle exercise at a workload of 25, 50, 75 watts. The following parameters were derived and averaged: mean velocity of flow across the mitral valve, mean mitral valve gradient, diastolic filling period and heart rate. The increase in mitral valve flow was from 1.5 +/- 0.3 to 2.2 +/- 0.5 m/s (p less than 0.001); the corresponding increase in mean pressure gradient was from 11 +/- 3 to 21 +/- 8 mmHg (p less than 0.001). The decrease in the diastolic filling period was from 424 +/- 170 to 272 +/- 73 msec (p less than 0.005). The increase in heart rate was from 60 +/- 10 to 100 +/- 18 beats/minute (p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)